Control for refrigerating systems



Feb. 23, 1937. G, MUF'FLY 2,071,935

V CONTROL FOR REFRIGERATING SYSTEMS original Filed'nec. 51. 192s z sheets-smet 1 GZennC/Wuffy Fel-m.l l23, 1937. G. MUFFLY CNTROL FOR REFRIGERATING SYSTEMS original Filed Dec. :51. 1923 2 sheets-sneek 2 Vl M my.

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75 ff/F0' w ATToR EYr pansion element is of sheet metal or other constructiom It will be obvious that as the pressure builds up in the expansion element I9 such pressure will be transmitted through the passages 34, 33 and 32 to the interior of the bellows 28 and will cause the same to expand and move the head 3| of the valve member 38 to close the opening`21. 'I'he particular pressure necessary in the bellows 28 to cause the head 3| to close the opening 21 may be adjustablyy controlled by rotating the cap 36 threadably received on the body 25 and between the end of which and the head 29 of the bellowsis positioned a coil spring 31 maintained under compression. Any other form of expansion valve or device adapted to be controlled by pressure within the expansion element to control the flow of refrigerant to the expansion element may be equally well employed in connection with the present invention.

Contrary to conventional practice, I insert in the suction line between the expansion element and the compressor I8 a control valve indicated generally as 2|.in Fig. 1 and whichv may take the form indicated in Fig. 3 which comprises a housing 48 having an inlet passage 4I adapted.

to be connected to receive refrigerant from the expansion element I9, and which is closed at the other end by a cap member 42 which may threadably engage the same and may be sealed against leakage by a gasket such as 43 or other suitable Iir'ieans.

The cap 42 is provided with a discharge passage 44 through which the refrigerant is i adapted to flow to the suction side of the compresser. Within the casing 48 is positioned a metallic bellows 45 preferably provided with a boss such as 46 on one end thereof adapted to be received in a depression such as 41 in the Vhousing 48 so as to hold it in proper relative position with respect to the housing. The opposite end of the bellows 45 is provided with a Valve member 48 secured thereto and which is adapted to cooperate with the valve seat 49 formed in the casing 48 to control the flow of refrigerant through the casing 48. A coil spring such as 58 is preferably provided and maintainedunder suitable compression betweenv the cap 42 and the .valve 48 so as to constantly tend to collapse the bellows 45 and move the valve 48 into contact with the valve seat 49 so as to cut off the flow of refrigerant through the housing 40. Lugs such as 5| may be provided on the cap 42 to prevent the valve 48 from opening to such an extent a`s v'to cut off the flow of refrigerant through the casing 48. -A check valve such as 53 may` be provided in cooperative relationship with a valve seat such as` 54 for preventing possibility of reversal of flow of refrigerant through the housing 48,511e desired, and in such case a stop membersuch as 55 may be provided for the valve disc 53.

The bellows 45 preferably contains a fluid A which may either be the same as the refrigerant employed in the system, or one which will liquefy at a slightly different temperature than the refrigerant employed in the system. The bellows 45 and the housing 48 are so proportioned that when the :fluid within the bellows 45 is under a relatively high vapor pressure the valve 48 is in 'open position with respect to the valve seat 49 so as to permit flow of refrigerant through the casing 48, and when the fluid in the bellows 45 is under a relatively low vapor pressure the bellows 45 is contracted a sufllcient amount to permit the spring 48 to seat the valve the expansion element I9 begins to collect liquid refrigerant therein and the gasified refrigerant passing through the housing 48 decreases in temperature, and some liquidrefrigerant may find its way into the housing 48 and become gasified therein, until enough of the uid within the bellows 45 is liquefied to permit the spring 58 to overcome the pressure in the bellows 45 and vclose the valve 48. As soon as this happens the expansion element I9 is cut off from the suction side of the compressor and the pressure within the expansion element I9 builds up and causes the expansion valve' I8 to close and thus shut off the flow of refrigerant to the expansion element I9. At the same time the pressure in the suction tube 28 drops and this drop in pressure is transmitted to the control device 22 which is thereby actuated, to break the circuit 23 between the motor II and source of electric energy 24. When a suilicient amount of the refrigerant in the expansion element I9 has been gasied and its temperature rises, a corresponding rise of temperature will occur in the fluid in the bellows 45 which will accordingly expand and force the valve 48 off the seat 49 against the pressure of the spring 50, and thus release the pressure in the expansion element I9 which accordingly will increase the pressure in the suction tube 28 and actuate the pressure switch 22 to start the motor Il, starting another cycle ofoperation.

In Fig. 4 a modied form of the valve shown in Fig. 3 is illustrated. 'I'he valve in this construction is of slightly modified Yform having a housing 68 provided withl an inlet passage 6| which is provided with a bridge as at 62 uponA which the bellows 63 is mounted. 'I'he bellows 83 is provided with a sheet metal head 64 which also serves as a valve for cooperation with the.

valve seat 65 toy control the flow of refrigerant through the housing 68. A coil spring 66 sim- 4casing and the recess 69 formed in the head 64.

of the bellows 63. The head 61 is of course provided with a discharge passage 69.

In the construction shown in Figs. 3 and 4 the valves are of relatively large diameter and consequently may be more sensitive to the effects of the suction of the compressor than is desirable, and in such cases a construction such as is indicated in Fig. 5 may be employed. The device shown. in Fig. 5 comprises a housing 15 having an inlet opening 16 provided with a bridge such as 11 which supports the bellows 18. 'I'he opposite end of the housing 15 is enclosed by the .head 19 and between the head 19 and the adjacent end of the bellows 18 is positioned a transverse Wall 88 having a central opening 88'. The bellows 18 is provided with a head 8| having a stem 82- projecting through the opening 8| in spaced 'relation with respect to the walls thereof. 'Ihe stem 82 may be of tubular formation to permit the introduction of the actuating iluid into the bel- 

